Hot deformation behavior of a martensitic stainless steel during hot deformation processes

Dynamic recrystallization (DRX) behavior of AISI 422 martensitic stainless steel has been investigated at deformation temperatures of 950- 1150 ºC and strain rates of 0.01- 1 s-1. The obtained results showed that the flow stress depends intensely on the deformation temperature and the strain rate, which it increases with the decreasing of deformation temperature andincreasing of strain rate. The critical stress for initiation of DRX was determined based onchange in strain hardening rate as a function of flow stress. The value of normalized critical stress for the alloy was estimated σc/σP=0.84. Furthermore, by considering the material constantsas a function of strain with a third polynomial fitting, the effect of strain was investigated using an Arrhenius type constitutive equation. The activation energy for DRX (Q) of this stainless steel was estimated to be an average of 420 kJ/mol.

کلیدواژه ها:

AISI 422 stainless steel ، dynamic recrystallization ، hot deformation ، constitutive equation